Modern vehicles are being equipped increasingly with autonomous driving (AD) systems. Operation of these systems is improved with accuracy of vehicle and environmental data available.
Advanced AD systems use data including road bank angle and vehicle roll angle, especially in turning and banked-road situations. The data can also include road grade and vehicle pitch angles.
Road bank angle and vehicle roll angle can be measured, directly, as can be road grade and vehicle pitch angles. The angles can be measured, for instance, using a dedicated optical sensor, and/or a multi-antenna satellite arrangement—e.g., Global Positioning System (GPS). A high-accuracy GPS unit can be placed at each of four corners of a vehicle to measure roll and pitch (and yaw) angles of the vehicle. These methods are very expensive, though, and not feasible within typical consumer price points.
Moreover, measurement data may have inaccuracies due to even slight measurement-device offset or error, noise, and/or failure of the system to still contextualize the measured data—e.g., even if roll-direction movement is accurately detected using GPS units, the system would require accurate road-bank angle data in order to properly determine what proportion of the measured roll-direction movement is due to vehicle roll as opposed to road bank.
The present technology solves these and other shortcomings by estimating accurately both vehicle roll angle and road bank angle, together, using a correcting observer software module applying a tuned observer gain.